External Defibrillator and Methods for Operating the External Defibrillator

ABSTRACT

Methods and apparatus are provided for minimizing the inherent time delays within external defibrillators. The methods and apparatuses utilize timing schemes for initiation and completion of charging of an energy storage device of an external defibrillator, measuring one or physical parameters of the patient and conducting a physiology analysis of the patient. The initiation and completion of one or more of these activities are arranged so that the energy storage device is charged to a desired level and available for a defibrillation shock to the patient with minimal delay after activation of the external defibrillator.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.60/412,340, filed Sep. 20, 2002.

TECHNICAL FIELD

The present invention generally relates to charging, and moreparticularly relates to an external defibrillator and methods ofoperating the external defibrillator.

BACKGROUND

A normal human heart pumping pattern is called a sinus rhythm, and isregulated by the body's biological pacemaker within the upper rightchamber of the heart, which is commonly referred to as the right atrium.This natural pacemaker, which is generally referred to as the sinoatrial(SA) node, sends electrical signals to the right and left ventricularmuscles in the lower chambers of the heart. The ventricular muscles thenimplement the pumping action under control of the SA node. The rightventricular muscle pumps blood to the lungs for oxygenation, and theleft ventricular muscle pumps the oxygenated blood to various parts ofthe body.

In certain circumstances, the normal or sinus heartbeat rhythm may beadversely affected as a result of some type of malfunction in theheart's electrical control system. When this type of malfunction occurs,an irregular heartbeat may result, causing the ventricular muscles topump ineffectively, thus reducing the amount of blood pumped to thebody. This irregular heartbeat is generally referred to as anarrhythmia.

A particularly serious arrhythmia is known as Ventricular Fibrillation(VF), which is a malfunction characterized by rapid, uncoordinatedcardiac movements replacing the normal contractions of the ventricularmuscles. In this event, the ventricular muscles are not able to pumpblood out of the heart, and there is no initiation of a heartbeat. VFrarely terminates spontaneously, and is therefore a leading cause ofsudden cardiac death. The unpredictability of VF and other irregularheat beat conditions exacerbates the problem, and emphasizes the needfor early therapeutic intervention to prevent the loss of life.

Defibrillators are devices for providing life-saving electrical shocktherapy to persons experiencing an irregular heat beat, such as VF. Adefibrillator provides an electrical shock to the heart, in order toconvert the irregular heat beat to a normal sinus rhythm. One type ofdefibrillator is surgically implanted in patients who are consideredlikely to need electrical shock therapy, precluding the necessity ofconstant monitoring by medical personnel.

A more commonly used type of defibrillator is the externaldefibrillator, which sends electrical shock pulses to the patient'sheart through external electrodes applied to the patient's chest.External defibrillators may be manually operated, as are typically usedin hospitals by medical personnel or may be semiautomatic,semi-automated, fully automatic, or fully automated devices, where theycan be used in any location where an unanticipated need may occur.

It is well known that time is an important factor in the successfulapplication of electrical shock therapy. According to recent data, thesurvival rate of persons suffering from ventricular fibrillationdecreases by about ten percent (10%) for each minute the administrationof a defibrillation shock is delayed. It is therefore desirable tominimize the time duration between powering up an external defibrillatorand administering the electrical shock therapy to the patient.

Prior to delivery of the defibrillation shock, the defibrillatorelectrodes are attached to the patient, the patient's condition andparameters are measured and analyzed, and a shock energy circuit ischarged to an appropriate level. One or more of these activities can bedone by medical/emergency personnel, as in the case of manualdefibrillators, or by an automatic or automated process, as in the caseof automatic, semi-automatic, automated and semi-automateddefibrillators. These actions are disadvantageously time-consuming, anddelay the administration of the shock therapy.

Accordingly, it is desirable to reduce the inherent time delaysassociated with shock administration in external defibrillators. Inaddition, it is desirable to implement delay reductions in all types ofexternal defibrillators, including fully automatic, semi-automatic,fully automated or semi-automated and manual defibrillators.Furthermore, other desirable features and characteristics of the presentinvention will become apparent from the subsequent detailed descriptionof the invention and the appended claims, taken in conjunction with theaccompanying drawings and this background of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will hereinafter be described in conjunction withthe following drawing figures, wherein like numerals denote likeelements, and

FIG. 1 is an illustration of an external defibrillator system connectedto a patient in accordance with an exemplary embodiment of the presentinvention;

FIG. 2 is a simplified block diagram of an external defibrillator inaccordance with a first exemplary embodiment of the invention;

FIG. 3 is a flowchart for the method of operating the externaldefibrillator of FIG. 2 in accordance with a first exemplary embodimentof the present invention;

FIG. 4 is an exemplary timing diagram for operating the externaldefibrillator of FIG. 2 in accordance with the first exemplaryembodiment of the present invention;

FIG. 5 is a flowchart for the method of operating the externaldefibrillator of FIG. 2 in accordance with a second exemplary embodimentof the present invention;

FIG. 6 is an exemplary timing diagram for operating the externaldefibrillator of FIG. 2 in accordance with the second exemplaryembodiment of the present invention;

FIG. 7 is a flowchart for operating the external defibrillator of FIG. 2in accordance with a third exemplary embodiment of the presentinvention;

FIG. 8 is an exemplary timing diagram for operating the externaldefibrillator of FIG. 2 in accordance with the third exemplaryembodiment of the present invention;

FIG. 9 is a flowchart for operating the external defibrillator of FIG. 2in accordance with a fourth exemplary embodiment of the presentinvention;

FIG. 10 is an exemplary timing diagram for operating the externaldefibrillator of FIG. 2 in accordance with the fourth exemplaryembodiment of the present invention;

FIG. 11 is a flowchart for operating the external defibrillator of FIG.2 in accordance with a fifth exemplary embodiment of the presentinvention;

FIG. 12 is a flowchart for operating the external defibrillator of FIG.2 in accordance with a sixth exemplary embodiment of the presentinvention; and

FIG. 13 is a flowchart for operating the external defibrillator of FIG.2 in accordance with a seventh exemplary embodiment of the presentinvention.

DETAILED DESCRIPTION

The following detailed description of the invention is merely exemplaryin nature and is not intended to limit the invention or the applicationand uses of the invention. Furthermore, there is no intention to bebound by any expressed or implied theory presented in the precedingbackground of the invention or the following detailed description of theinvention.

FIG. 1 is a defibrillator system 20 that is configured to deliver adefibrillation shock to a patient 22, such as a victim of VF. Thedefibrillator system 20, includes, but is not limited to, an externaldefibrillator 24 having a connection port 26 that is configured toreceive one or more electrodes (32,34). The external defibrillator 24can be any number of external defibrillators in accordance with thepresent invention. For example, the external defibrillator 24 can be anAutomatic External Defibrillator or Automated External Defibrillator(AED), semi-Automatic or semi-Automated External Defibrillator, or amanually operated external defibrillator. As used herein, an automaticor automated activity occurs without human intervention. While many ofthe exemplary embodiments of the invention apply to all types ofexternal defibrillators, some of the embodiments are only for specifictypes, such as embodiments only for manual defibrillators, only forautomated, or only for semi-automated.

The external defibrillator 24 preferably includes a user interface 27having a display 28 that is configured to visually present variousmeasured or calculated parameters of patient 22 and/or other informationto the operator (not shown) of the external defibrillator 24. Forexample, the display 28 can be configured to visually present thetransthoracic impedance, ElectroCardioGram (ECG) and/or other physiologysignals of the patient. The user interface 27 can also include one ormore input devices (e.g., switches or buttons) 30 that are configured toreceive commands or information from the operator. The externaldefibrillator 24 is configured generate a charge that is delivered tothe patient 22 as the defibrillation shock with one or more electrodes(32, 34).

The one or more electrodes (32, 34) and/or one or more sensingelectrodes (36, 38) are also configured to sense one or more physiologyand/or physical parameters of the patient 22 that are received by theexternal defibrillator 24 at the connection port 26. The signalsprovided by the one more electrodes (32,34) and/or one more sensingelectrodes (36,38) are preferably evaluated by the externaldefibrillator 24 to determine, among other things, whether adefibrillation shock should be applied to patient 22 in accordance withtechniques known to those of ordinary skill in the art. This externaldefibrillator 24 can also evaluate the signals provided by the one moreelectrodes (32,34) and/or one more sensing electrodes (36,38) todetermination the waveform parameters of the defibrillation shock (e.g.,sinusoidal, monophasic, biphasic, truncated) as well as magnitude andduration.

Referring to FIG. 2, a simplified block diagram of the externaldefibrillator 24 is illustrated in accordance with an exemplaryembodiment of the present invention. The external defibrillator 24preferably includes a controller 40, the user interface 27 (e.g.,switches or buttons 30 and/or display 28 as shown in FIG. 1), apre-amplifier/measuring circuit 42, a charging mechanism 44 that caninclude a power source 46 and a switch 48 to couple the power source 46to the one or more energy storage devices (e.g., capacitors) 50 and anenergy delivery circuit 52, which is illustrated as a switch 56 that isconfigured to selectively couple the one or more energy storage devices50 to the connection port 26 under the control of the controller 40. Theenergy delivery circuit 52 can be implemented with any number of circuitconfigurations. For example, in a biphasic circuit, an H-bridge circuitcan be used in accordance with the present invention. The controller 40can be a single processing unit or multiple processing units and can beimplemented with software, hardware, or a combination of hardware andsoftware. The controller 40 is configured to at least partially controlthe operation of the external defibrillator 24, including control ofcharging the one or more energy storage devices 50.

Referring to FIG. 3, a flowchart is presented that illustrates a method300 of operating the external defibrillator of FIG. 2 in accordance witha first exemplary embodiment of the present invention. The method 300begins with the charging of one or more energy storage devices of theexternal defibrillator 302. After beginning to charge the one or moreenergy storage devices 302, a physiology analysis of the patient isinitiated without human intervention (i.e., an automatic or automatedactivity) 304. A physical parameter of the patient is determined 306 anda charging level is determined based at least partially on the physicalparameter 308. In addition, a rate to charge the energy storage deviceis determined based at least partially on the physiology analysis 310and the defibrillation shock is applied to the patient without humanintervention 312.

Referring to FIG. 4, a timing diagram 54 is presented that illustratesan example with greater detail for the operating of the externaldefibrillator in accordance with the first exemplary embodimentillustrated in FIG. 3. While the events presented in the timing diagramare shown as beginning and ending at the same time instant, it should beappreciated that delays can exist and the events do not need to beginand end at the same time instant as illustrated in FIG. 4. Rather, oneevent can end before or after another time event.

The external defibrillator 24 is activated at an initial time instant(t₀). This activation can be accomplished using any number of techniquessuch activation of an input switch 30 as shown in FIG. 1. Afteractivation of the external defibrillator 24 at the initial time instant(t₀), one or more physical parameters of the patient are measured withthe one or more of the electrodes (32,34,36,38) at a first time instant(t₁). Any number of physical parameters can be measured in accordancewith the present invention. For example, the physical parameter can bethe transthoracic impedance between at least two of the electrodes(32,34,36,38). The signal or signals associated with the one or morephysical parameters are preferably provided to thepre-amplifier/measuring circuit 42 for preprocessing and/oramplification. The controller 40 receives the physical parameter anddetermines one or more charging parameters beginning at a second timeinstant (t₂). One of the charging parameters determined by thecontroller 40, which is at least partially based upon the physicalparameter, is a charge for the one or more energy storage devices 50that provides the desired defibrillation shock for the patient. Thisdetermination can be accomplished using any number of techniques knownto those of ordinary skill in the art. The one or more energy storagedevices 50 can be charged at any suitable rate, including, but notlimited to fixed or preset charging rates, computed charging rates,rates that can be adjusted prior to and/or during charging based uponany number of factors such as the results of a physiology analysis. Inaddition, the charging of the one or more energy storage devices 50 canbe accomplished using any number of charging apparatuses (e.g., one ormore charging circuits) that are preferably controlled by the controller40.

In addition to determining the charge, the controller 40 also preferablydetermines a charging rate to substantially achieve the charge no lessthan about a fifth time instant (t₅) prior to completion of a physiologyanalysis at a sixth time instant (t₆), which preferably began at afourth time instant (t₄). In addition, the controller 40 also preferablydetermines the charging rate to substantially achieve the charge no morethan about a seventh time instant (t₇) after completion of thephysiology analysis at the sixth time instant (t₆). The charging ratecan be determined using any number of techniques. For example thecharging rate (Q_(Rate)) can be determined as follows:Q _(Rate)=(Q _(Initial) −Q _(final))/Time_(Analysis)  (1)Where Q_(Initial) is magnitude of the initial charge when chargingbegins, Q_(final) is magnitude of the final charge (i.e., the charge forthe one or more energy storage devices 50 that provides the desireddefibrillation shock for the patient) and Time_(Analysis) is the time ittakes to complete the physiology analysis, which can be the minimumtime, maximum time, or average time to complete the physiology analysis.The minimum time, maximum time or average time will vary depending uponthe measurement scheme and physiology analysis conducted by thecontroller 40. The physiology analysis can be any number analyses usedto determine whether a defibrillation shock is preferably applied to thepatient. For example, an ECG analysis can be conducted in accordancewith techniques known to those of ordinary skill in the art based atleast partially upon an ECG signal received by the controller 40 fromthe preamplifier/measuring circuit 42.

After the physiology analysis and the charge is substantially completed,which is no later than the seventh time instant (t₇) as previouslydescribed in this detailed description, and if the physiology analysisindicates it is appropriate to provide a defibrillation shock to thepatient, the controller 40 can he configured to automatically initiatethe appropriate action(s) to couple the one or more charged energystorage device(s) 50 to the patient and/or the controller 40 can requestan operator request prior to initiating the appropriate action(s) tocouple the one or more charged energy storage device(s) 50 to thepatient. For example, the appropriate action(s) initiated by thecontroller 40 to couple the one or more charged energy storage device(s)to the patient can including closing a switch 56 of the energy deliverycircuit 52 to couple the one or more energy storage devices 50 to two ormore of the electrodes attached to the patient.

In accordance with the present invention, the controller 40 ispreferably configured to operate such that the seventh time instant (t₇)is greater than the sixth time instant (t₆), the sixth time instant (t₆)is greater than the fifth time instant (t₅), the fifth time instant (t₅)is greater than the fourth time instant (t₄), the fourth time instant(t₄) is greater than the third time instant (t₃), the third time instant(t₃) is greater than the second time instant (t₂) the second timeinstant (t₂) is greater than the first time instant (t₁), and the firsttime instant (t₁) is greater than the initial time. Moreover, the fourthtime instant (t₄) is substantially equal to the third time instant (t₃).Furthermore, the fifth time instant (t₅) and/or the seventh time instant(t₇) are preferably within five (5) seconds of the sixth time instant(t₆), more preferably within two (2) seconds of the sixth time instant(t₆), and even more preferably within one (1) second of the sixth timeinstant (t₆).

Referring to FIG. 5, a flowchart is presented that illustrates a method500 of operating the external defibrillator in accordance with a secondexemplary embodiment of the present invention. The method 500 begins byinitiating a physiology analysis of the patient 502 and measuring aphysical parameter of the patient 504. A charge for the energy storagedevice is determined based at least partially on the physical parameter506 and the charging of the energy storage devices is initiated 506after initiating the physiology analysis of the patient 502 and beforethe completion of the physiology analysis 508. Lastly, thedefibrillation shock is applied to the patient without humanintervention 510 (i.e., an automatic or automated activity).

Referring to FIG. 6, a timing diagram 56 is presented that illustratesan example with greater detail for the operating of the externaldefibrillator in accordance with the second exemplary embodimentillustrated in FIG. 5. Referring to FIG. 6 in conjunction withcontinuing reference to FIG. 2, a timing diagram 56 is presented thatillustrates the charging of the one or more energy storage devices 50 ofthe external defibrillator 24 in accordance with a second exemplaryembodiment of the present invention. While the events presented in thetiming diagram are shown as beginning and ending at the same timeinstant, it should be appreciated that delays can exist and the eventsdo not need to begin and end at the same time instant as illustrated inFIG. 6. Rather, one event can end before or after another time event.

The external defibrillator 24 is activated at an initial time instant(t₀). This activation can be accomplished using any number of techniquessuch activation of an input switch 30 as shown in FIG. 1. Afteractivation of the external defibrillator 24 at the initial time instant(t₀), a physiology analysis begins at a first time instant (t₁) andcompletes at a sixth time instant (t₆). As previously described in thisdetailed description, the physiology analysis can be any number analysesused to determine whether a defibrillation shock is preferably appliedto the patient. For example, an ECG analysis can be conducted inaccordance with techniques known to those of ordinary skill in the artbased at least partially upon an ECG signal received by the controller40 from the preamplifier/measuring circuit 42.

After the physiology analysis begins at the first time instant (t₁) andprior to completion of the physiology analysis at the sixth time instant(t₆), a charge of the one or more energy storage devices 50 is initiatedat a fourth time instant (t₄). Prior to initiating the charge of the oneor more energy storage devices 50 at the fourth time instant (t₄) one ormore physical parameters of the patient are preferably measured with theone or more of the electrodes (32,34,36,38) at a second time instant(t₂). Any number of physical parameters can be measured in accordancewith the present invention. For example, the physical parameter can bethe transthoracic impedance between at least two of the electrodes(32,34,36,38). The signal or signals associated with the one or morephysical parameters are preferably provided to thepre-amplifier/measuring circuit 42 for preprocessing and/oramplification. The controller 40 receives the physical parameter anddetermines one or more charging parameters beginning at a third timeinstant (t₃). The one of the charging parameters determined by thecontroller 40, which is at least partially based upon the physicalparameter, is the charge for the one or more energy storage devices 50that provides the desired defibrillation shock for the patient. Thisdetermination can be accomplished using any number of techniques knownto those of ordinary skill in the art.

In addition to determining the charge, the controller 40 also preferablydetermines a charging rate to substantially achieve the charge no lessthan about a fifth time instant (t₅) prior to completion of a physiologyanalysis at the sixth time instant (t₆). In addition, the controller 40also preferably determines the charging rate to substantially achievethe charge no more than about a seventh time instant (t₇) aftercompletion of the physiology analysis at the sixth time instant (t₆).The rate can be determined using any number of techniques, such as thecalculation of equation (1).

After the charge and charging rate are determined, the charge of the oneor more energy storage devices is substantially completed, thephysiology analysis is substantially completed, which is no later thanthe seventh time instant (t₇), and if the physiology analysis indicatesit is appropriate to provide a defibrillation shock to the patient, thecontroller 40 can he configured to automatically initiate theappropriate action(s) to couple the one or more charged energy storagedevice(s) 50 to the patient and/or the controller 40 can request anoperator request prior to initiating the appropriate action(s) to couplethe one or more charged energy storage device(s) 50 to the patient. Forexample, the appropriate action(s) initiated by the controller 40 tocouple the one or more charged energy storage device(s) to the patientcan including closing a switch 56 of the energy delivery circuit 52 tocouple the one or more energy storage devices 50 to two or more of theelectrodes attached to the patient.

In accordance with the controller 40 is preferably configured to operatesuch that the seventh time instant (t₇) is greater than the sixth timeinstant (t₆), the sixth time instant (t₆) is greater than the fifth timeinstant (t₅), the fifth time instant (t₅) is greater than the fourthtime instant (t₄), the fourth time instant (t₄) is greater than thethird time instant (t₃), the third time instant (t₃) is greater than thesecond time instant (t₂), the second time instant (t₂) is greater thanthe first time instant (t₁), and the first time instant (t₁) is greaterthan the initial time. Moreover, the fourth time instant (t₄) ispreferably substantially equal to the third time instant (t₃).Furthermore, the fifth time instant (t₅) and/or the seventh time instant(t₇) are preferably within five (5) seconds of the sixth time instant(t₆), more preferably within two (2) seconds of the sixth time instant(t₆), and even more preferably within one (1) second of the sixth timeinstant (t₆).

Referring to FIG. 7, a flowchart is presented that illustrates a method700 of operating the external defibrillator of FIG. 2 in accordance witha third exemplary embodiment of the present invention. The method 700begins by charging an energy storage device of the externaldefibrillator to a first charge level 702 and measuring a physicalparameter of the patient 704. A second charge level is determined basedat least in part on the physical parameter of the patient 706 and theenergy storage device is discharged from the first charge level to thesecond charge level 708. A physiology analysis of the patient isconducted 710 and the defibrillation shock is applied to the patient.

Referring to FIG. 8, a timing diagram 58 is presented that illustratesan example with greater detail for the operating of the externaldefibrillator in accordance with the third exemplary embodimentillustrated in FIG. 7. Referring to FIG. 8 in conjunction withcontinuing reference to FIG. 2, a timing diagram 58 is presented thatillustrates the charging of the one or more energy storage devices 50 ofthe external defibrillator 24 in accordance with a third exemplaryembodiment of the present invention. While the events presented in thetiming diagram are shown as beginning and ending at the same timeinstant, it should be appreciated that delays can exist and the eventsdo not need to begin and end at the same time instant as illustrated inFIG. 8. Rather, one event can end before or after another time event.

The external defibrillator 24 is activated at an initial time instant(t₀). This activation can be accomplished using any number of techniquessuch activation of an input switch 30 as shown in FIG. 1. Afteractivation of the external defibrillator 24 at the initial time instant(t₀), the one or more energy storage devices 50 are charged to a firstcharge level at a first time instant (t₁). The first charge level ispreferably greater than about fifty percent (50%) of the maximum chargefor the one or more energy storage devices 50, more preferably greaterthan about seventy-five percent (75%) of the maximum charge of the oneor more energy storage devices 50 and even more preferably greater thanabout ninety percent (90%) of the maximum charge of the one or moreenergy storage devices 50. After the first charge level is reached, theone or more physical parameters of the patient are preferably measuredwith the one or more of the electrodes (32,34,36,38) at a second timeinstant (t₂) as shown in FIG. 1.

Any number of physical parameters can be measured in accordance with thepresent invention. For example, the physical parameter can be thetransthoracic impedance between at least two of the electrodes(32,34,36,38). The signal or signals associated with the one or morephysical parameters are preferably provided to thepre-amplifier/measuring circuit 42 for preprocessing and/oramplification. The controller 40 receives the physical parameter anddetermines one or more charging parameters beginning at a third timeinstant (t₃). The one of the charging parameters determined by thecontroller 40, which is at least partially based upon the physicalparameter, is the charge for the one or more energy storage devices 50that provides the desired defibrillation shock for the patient. Thisdetermination can be accomplished using any number of techniques knownto those of ordinary skill in the art.

After the one or more charging parameters are determined by thecontroller, the one or more energy storage devices 50 that werepreviously charged are discharged at a fourth time instant (t₄). Thedischarge is conducted to decrease the charge of the one or more energystorage devices 50 from the first charge level to the charge thatprovides the desired defibrillation shock for the patient. Thisdischarge at the fourth time instant (t₄) is followed by a physiologyanalysis that begins at a fifth time instant (t₅) and completes at asixth time instant (t₆). As previously described in this detaileddescription, the physiology analysis can he any number analyses used todetermine whether a defibrillation shock is preferably applied to thepatient. For example, an ECG analysis can be conducted in accordancewith techniques known to those of ordinary skill in the art based atleast partially upon an ECG signal received by the controller 40 fromthe preamplifier/measuring circuit 42.

After the physiology analysis is completed at the sixth time instant(t₁), the controller 40 can be configured to automatically initiate theappropriate action(s) to couple the one or more charged energy storagedevice(s) 50 to the patient and/or the controller 40 can request anoperator request prior to initiating the appropriate action(s) to couplethe one or more charged energy storage device(s) 50 to the patient ifthe physiology analysis indicates the desirability of such adefibrillation shock. For example, the appropriate action(s) initiatedby the controller 40 to couple the one or more charged energy storagedevice(s) to the patient can including closing a switch 56 of the energydelivery circuit 52 to couple the one or more energy storage devices 50to two or more of the electrodes attached to the patient.

The foregoing methods and configurations of the external defibrillatorpreferably provide the charge for the initial defibrillation shock afterinitial activation of the external defibrillator. However, additionaldefibrillation shocks can be provided after the initial defibrillationshock in order to return the heart rhythm to a sinus rhythm, Inaddition, the one or more energy storage devices can be charged and adetermination can be made that a defibrillation shock is inadvisable. Insuch a situation, the charge in the one or more energy storage devicescan be discharged into other devices such a resistor. Alternatively, thecharge can be maintained for future availability if a determination issubsequently made that a defibrillation shock is advisable.

Referring to FIG. 9, a flowchart is presented that illustrates a method900 of operating the external defibrillator of FIG. 2 in accordance witha fourth exemplary embodiment of the present invention. The method 900begins by determining a rate to charge the energy storage device toachieve a first charge level used for an initial defibrillation shock ofthe patient 702 and charging the energy storage device at the rate 704.A physiology analysis of the patient is conducted 906 and completedafter substantially achieving the first charge level 908. Once thephysiology analysis of the patient is competed 908, a subsequentdefibrillation shock is applied to the patient 910.

Referring to FIG. 10, a timing diagram 60 is presented that illustratesan example with greater detail for the operating of the externaldefibrillator 24 in after an initial defibrillation shock is provided atan initial time instant (t₀) in accordance with the fourth exemplaryembodiment illustrated in FIG. 9. While the events presented in thetiming diagram are shown as beginning and ending at the same timeinstant, it should be appreciated that delays can exist and the eventsdo not need to begin and end at the same time instant as illustrated inFIG. 9. Rather, one event can end before or after another time event.

After the initial defibrillation shock is provided at the initial timeinstant (t₀) with the charge stored in the one or more energy storage,the controller 40 receives determines one or more charging parametersbeginning at a first time instant (t₁), and preferably determines thecharging rate to substantially achieve the charge of the initialdefibrillation shock no less than about a fourth time instant (t₄) priorto completion of a physiology analysis at a fifth time instant (t₅),which preferably began at a third time instant (t₃). In addition, thecontroller 40 also preferably determines the charging rate to charge theone or more energy storage devices, which were discharged for thedefibrillation shock (t₂), beginning a second time instant (t₂) tosubstantially achieve the charge of the initial defibrillation shock nomore than about a sixth time instant (t₆) after completion of thephysiology analysis at the fifth time instant (t₅). The rate can bedetermined using any number of techniques. For example the charging rate(Q_(Rate)) can be determined using equation (1), where Q_(Initial) ischarge of the one or more energy storage devices 50 after the initialdefibrillation shock, Q_(final) is charge of the one or more energystorage devices 50 prior to the initial defibrillation shock andTime_(Analysis) is the time it takes to complete the physiologyanalysis, which can be the minimum time, maximum time, or average timeto complete such a physiology analysis. The minimum time, maximum timeor average time will vary depending upon the measurement scheme andphysiology analysis conducted by the controller 40. The physiologyanalysis can be any number analyses used to determine whether adefibrillation shock is preferably applied to the patient. For example,an ECG analysis can be conducted in accordance with techniques known tothose of ordinary skill in the art based at least partially upon an ECGsignal received by the controller 40 from the preamplifier/measuringcircuit 42.

After the physiology analysis and the charge is substantially completed,which is no later than the sixth time instant (t₆), and if thephysiology analysis indicates it is appropriate to provide adefibrillation shock to the patient, the controller 40 can be configuredto increase or decrease the charge level (i.e., adjust the charge level)and also configured to automatically initiate the appropriate action(s)to couple the one or more charged energy storage device(s) 50 to thepatient and/or the controller 40 can request an operator request priorto initiating the appropriate action(s) to couple the one or morecharged energy storage device(s) 50 to the patient. For example, theappropriate action(s) initiated by the controller 40 to couple the oneor more charged energy storage device(s) to the patient can includingclosing a switch 56 of the energy delivery circuit 52 to couple the oneor more energy storage devices 50 to two or more of the electrodesattached to the patient.

In accordance with the controller 40 is preferably configured to operatesuch that the sixth time instant (t₆) is greater than the fifth timeinstant (t₅), the fifth time instant (t₅) is greater than the fourthtime instant (t₄), the fourth time instant (t₄) is greater than thethird time instant (t₃), the third time instant (t₃) is greater than thesecond time instant (t₂), the second time instant (t₂) is greater thanthe first time instant (t₁), and the first time instant (t₁) is greaterthan the initial time. Moreover, the third time instant (t3) ispreferably substantially equal to the second time instant (t₂).Furthermore, the fourth time instant (t₄) and/or the sixth time instant(t₆) are preferably within five (5) seconds of the fifth time instant(t₅), more preferably within two (2) seconds of the fifth time instant(t₅), and even more preferably within one (1) second of the fifth timeinstant (t₅).

Referring to FIG. 11, a flowchart is presented that illustrates a method1100 of operating the external defibrillator of FIG. 2 in accordancewith a fifth exemplary embodiment of the present invention. The method1100 begins with sensing a first input for powering the externaldefibrillator 1102. The first input can be any number of inputs such asa power button of the user interface. In response to sensing the firstinput or in response to an initial powering up of the externaldefibrillator, the method 1100 initiates the charging of the energystorage devices of the external defibrillator 1104. Optionally, themethod 1100 continues with the disablement of a firing input, such as ashock button of the user interface, while the charging the energystorage devices 1106. Furthermore, the method 110 optionally continueswith sensing a preparatory input 1108, such as an analyze input orcharge input of the user interface, and enabling the firing input inresponse to sensing the preparatory input 1110. The method 1100 receivesthe firing input that requests delivery of the defibrillation shock1112, and delivering the defibrillation shock in response to receivingthe firing input, which occurs without the external defibrillatorconducting a physiology analysis of the patient 1114.

Referring to FIG. 12, a flowchart is presented that illustrates a method1200 of operating the external defibrillator of FIG. 2 in accordancewith a sixth exemplary embodiment of the present invention. The method1200 begins with the delivery of an initial defibrillation shock 1202and beginning to charge an energy storage device of the externaldefibrillator as a result of the delivery of the initial defibrillationshock and without human intervention 1204. A physiology analysis of thepatient is initiated after beginning to charge the energy storage device1206 and a subsequent defibrillation shock is delivered without humanintervention after initiating the physiology analysis 1208.

Referring to FIG. 13, a flowchart is presented that illustrates a method1300 of operating the external defibrillator of FIG. 2 in accordancewith a seventh exemplary embodiment of the present invention. The method1300 begins with an activation of the external defibrillator 1302 andsensing application of at least one of the plurality of electrodes tothe patient 1304, which as known to those of ordinary skill in the artwill alter an electrical property seen by the external defibrillator(e.g., a sudden increase in the impedance measured across the electrodes(e.g., twenty (20Ω) ohms to thirty ohms (300Ω) will be seen when theelectrodes are attached to the patient. The method 1300 continues withthe measuring a physical parameter of the patient 1306, initiating thecharging of the external defibrillator to achieve an energy level for atleast one energy storage device of the external defibrillator 1308,conducting a physiology analysis of the patient in order to determine adesirability for application of a defibrillation shock to the patient1310 and delivering the defibrillation shock to the patient through theplurality of electrodes if said desirability for application of thedefibrillation shock to the patient exists 1312.

In view of the foregoing, it should be appreciated that methods andapparatus are available that minimize the inherent time delay betweendefibrillator activation and the administration of a defibrillationshock therapy. While a finite number of exemplary embodiments have beenpresented in the foregoing detailed description of the invention, itshould be appreciated that a vast number of variations exist. It shouldalso he appreciated that the exemplary embodiments are only examples,and are not intended to limit the scope, applicability, or configurationof the invention in any way. Rather, the foregoing detailed descriptionwill provide those skilled in the art with a convenient road map forimplementing exemplary embodiments of the invention. It being understoodthat various changes may be made in the function and arrangement ofelements described in an exemplary embodiment without departing from thescope of the invention as set forth in the appended claims.

1.-25. (canceled)
 26. An external defibrillator that is configured toprovide a defibrillation shock through a plurality of electrodesattached to a patient, comprising: a connection port configured tocouple the external defibrillator to the plurality of electrodes; anenergy storage device coupled to said plurality of electrodes; and acontroller coupled to said plurality of electrodes and said energystorage device, said controller configured to: measure a physicalparameter of the patient at about a first time instant (t₁); determine acharge for the energy storage device at about a second time instant (t₂)that is at least partially based on said physical parameter; complete aphysiology analysis of the patient at about a sixth time instant (t₆);determine a rate for charging said energy storage device tosubstantially achieve said charge after about a fifth time instant (t₅)and before about a seventh time instant (t₇), said fifth time occurringbefore about said sixth time instant (t₆) and said seventh time instant(t₇) occurring after about said sixth time instant (t₆); and begin tocharge said energy storage device at said rate at about a third timeinstant (t₃).
 27. The external defibrillator of claim 26, saidcontroller further configured to begin said physiology analysis at abouta fourth time instant (t₄).
 28. The external defibrillator of claim 27,said controller further configured to activate at an initial timeinstant (t₀).
 29. The external defibrillator of claim 26, wherein saidphysical parameter is a transthoracic impedance.
 30. The externaldefibrillator of claim 26, wherein said physiology analysis is an ECGanalysis.
 31. The external defibrillator of claim 28, wherein saidseventh time instant (t₇) is greater than said sixth time instant (t₆),said sixth time instant (t₆) is greater than said fifth time instant(t₅), said fifth time instant (t₅) is greater than said fourth timeinstant (t₄), said fourth time instant (t₄) is greater than said thirdtime instant (t₃), said third time instant (t₃) is greater than saidsecond time instant (t₂), said second time instant (t₂) is greater thansaid first time instant (t₁), and said first time instant (t₁) isgreater than said initial time instant (t₀).
 32. The externaldefibrillator of claim 27, wherein said fourth time instant (t₄) issubstantially equal to said third time instant (t₃).
 33. The externaldefibrillator of claim 26, wherein said fifth time instant (t₅) iswithin about two (2) seconds of said sixth time instant (t₆).
 34. Theexternal defibrillator of claim 26, wherein said seventh time instant(t₇) is within about two (2) seconds of said sixth time instant (t₆).35.-42. (canceled)
 43. An external defibrillator that is configured toprovide a defibrillation shock through a plurality of electrodesattached to a patient, comprising: a connection port configured tocouple the external defibrillator to the plurality of electrodes; anenergy storage device coupled to said plurality of electrodes; and acontroller coupled to said plurality of electrodes and said energystorage device, said controller configured to: initiate a physiologyanalysis of the patient at about a first time instant (t₁); completesaid physiology analysis of the patient at about a sixth time instant(t₆); initiate a charge of said energy storage device at about a fourthtime instant (t₄), said fourth time instant (t₄) occurring afterinitiating said physiology analysis at about said first time instant(t₁) and before completing said physiology analysis at about said sixthtime instant (t₆); and apply the defibrillation shock to the patientwithout human intervention at about a seventh time instant (t₇)occurring after said initiating said charge of said energy storagedevice at about said fourth time instant (t₄).
 44. The externaldefibrillator of claim 43, said controller further configured to:measure a physical parameter of the patient at about a first timeinstant (t₂); determine a charge for the energy storage device at abouta third time instant (t₃) that is at least partially based on saidphysical parameter; and determine a rate for charging said energystorage device to substantially achieve said charge after about a fifthtime instant (t₅) and before about said seventh time instant (t₇), saidfifth time instant (t₅) occurring before about said sixth time instant(t₆) and said seventh time instant (t₇) occurring after about said sixthtime instant (t₆).
 45. The external defibrillator of claim 44, furthercomprising the step of activating said external defibrillator at aninitial time instant (t₀).
 46. The external defibrillator of claim 44,wherein said physical parameter is a transthoracic impedance.
 47. Theexternal defibrillator of claim 43, wherein said physiology analysis isan ECG analysis.
 48. The external defibrillator of claim 45, whereinsaid seventh time instant (t₇) is greater than said sixth time instant(t₆), said sixth time instant (t₆) is greater than said fifth timeinstant (t₅), said fifth time instant (t₅) is greater than said fourthtime instant (t₄), said fourth time instant (t₄) is greater than saidthird time instant (t₃), said third time instant (t₃) is greater thansaid second time instant (t₂), said second time instant (t₂) is greaterthan said first time instant (t₁), and said first time instant (t₁) isgreater than said initial time instant (t₀).
 49. The externaldefibrillator of claim 44, wherein said fifth time instant (t₅) iswithin about two (2) seconds of said sixth time instant (t₆).
 50. Theexternal defibrillator of claim 44, wherein said seventh time instant(t₇) is within about two (2) seconds of said sixth time instant (t₆).51.-68. (canceled)
 69. An external defibrillator that is configured toprovide a subsequent defibrillation shock through a plurality ofelectrodes attached to a patient after an initial defibrillation shockis provided through the plurality of electrodes, comprising: aconnection port configured to couple the external defibrillator to theplurality of electrodes; an energy storage device coupled to saidplurality of electrodes; and a controller coupled to said plurality ofelectrodes and said energy storage device, said controller configuredto: complete a physiology analysis of the patient; and charge saidenergy storage device to substantially achieve a first charge used forsaid initial defibrillation shock before about said competing saidphysiology analysis of the patient.
 70. The external defibrillator ofclaim 69, said controller further configured to: determine a rate tocharge said energy storage device to substantially achieve said firstcharge; and charge said energy storage device at said rate.
 71. Theexternal defibrillator of claim 69, wherein said physiology analysis isan ECG analysis. 72.-78. (canceled)
 79. An external defibrillator thatis configured to provide a defibrillation shock through a plurality ofelectrodes attached to a patient, comprising: a connection portconfigured to couple the external defibrillator to the plurality ofelectrodes; an energy storage device coupled to said plurality ofelectrodes; and a controller coupled to said plurality of electrodes andsaid energy storage device, said controller configured to: deliver aninitial defibrillation shock; begin to charge an energy storage deviceof said external defibrillator as a result of delivering the initialdefibrillation shock and without human intervention; and deliver thesubsequent defibrillation.
 80. The external defibrillator that isconfigured to provide the defibrillation shock through the plurality ofelectrodes attached to the patient of claim 79, wherein said processoris further configured to initiate a physiology analysis after saidbeginning to charge said energy storage device.
 81. The externaldefibrillator that is configured to provide the defibrillation shockthrough the plurality of electrodes attached to the patient of claim 79,wherein the processor is configured to deliver the subsequentdefibrillation shock without human intervention. 82.-83. (canceled)